Electrostatic copiers have been provided with endless-web-type photoreceptors; and with suitable means for advancing the photoreceptors from a storage station through several processing stations and then back to the storage station; and with suitable means for storing the photoreceptor at the storage station. For example, in the copier disclosed in U.S. Pat. No. 3,481,048, issued Mar. 16, 1976, there is disclosed apparatus for storing a photoreceptor having a plurality of sections in a stack. Such apparatus includes an elongated receptacle having a generally U-shaped transverse cross-section formed by a pair of oppositely disposed walls. The walls define an upper inlet opening through which processed photoreceptor sections are successively fed to the top of the stack, and a lower outlet opening through which stored photoreceptor sections are successively fed from the bottom of the stack. The receptacle walls extend downwardly and convergently toward one another from the inlet opening to the outlet opening, for guiding the folds of the photoreceptor sections progressively closer to the outlet opening than the mid-portions thereof in transit through the receptacle. With this arrangement the stack is bowed upwardly within the receptacle to facilitate feeding the sections from the bottom of the stack. The photoreceptor storing apparatus also includes a pair of tamping devices, slidably attached to the opposite receptacle walls, and a pair of suitably driven rocker arms arranged to alternately lift and lower the tamping devices against the opposite folds of the photoreceptor sections as they are fed to the top of the stack. The tamping devices thus cooperate with the receptacle walls in guiding the folds of the photoreceptor sections below the level of their respective mid-portions.
In the above described arrangement of apparatus the photoreceptor sections move in surface to surface contact with each other when stored in the stack. As a consequence, the photoconductive surfaces of photoreceptor sections are abraded, which may result in premature termination of the usefulness of the photoreceptor. In addition, the photoreceptor sections often become sufficiently triboelectrically charged during storage that they cannot thereafter be uniformly charged prior to imaging with the result that inferior images are formed on the photoreceptor sections. In addition, since the photoreceptor is not transported through the storage station, but rather is guided both to and through the same, the storing apparatus tends to permit a build-up of photoreceptor sections at the entry to the receptacle, as a result of which the photoreceptor is easily damaged.
Further, although there are other factors which contribute to low copy-per-minute speeds of the copier, since the photoreceptor structurally comprises a plurality of sections adapted to be stored in zig-zag folded stack in the receptacle, the photoreceptor includes a series of sharp folds rather than wavy loops formed in the same at spaced intervals along its length, which may ultimately limit the speed of feeding the photoreceptor to and away from the storage station; thereby limiting the reproductive capacity of the copier to relatively low copy-per-minute speeds. Of course, since the aforesaid zig-zag folds eventually weaken, they impose a limitation on the useful life of the photoreceptor. Further the zig-zag folds respectively constitute portions of the length of the photoreceptor on which images cannot be formed, as a consequence of which the control system of the copier must continuously recognize the presence of the folds in the course of advancement of the photoreceptor through the various processing instrumentalities of the copier, in order to timely operate the various instrumentalities in synchronism with advancement of a given photoreceptor section.